Button portion of an amplifier



FIG. 1 is a perspective view of a button portion of an amplifier showing our new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a left side elevational view thereof, the right side elevational view being a mirror image;

FIG. 4 is a front elevational view thereof; and,

FIG. 5 is a bottom plan view thereof.

The amplifier body portion in broken lines is for illustrative purpose only and forms no part of claimed design. 

The ornamental design for a button portion of an amplifier, as shown and described. 